This invention pertains to a delivery system for administering topical ophthalmic drug preparations, enabling the patient to direct an eye drop into the eye with the ease and accuracy previously only attained by a proficient few. In addition, this particular device may serve to prevent cross-contamination, and ultimately save both the patient and the healthcare system money typically lost to waste.
More specifically, this invention relates to a lens and target system which, when combined with or coupled to any standard topical ophthalmic drug dispensing unit, enables the user to view the target, align the dispenser tip, and administer an eye drop with precision not attained before. To achieve this precision, the target and lens system is calibrated to align with the axis of the eye at a specified distance. The nozzle of the dispenser is aligned adjacent to the target creating the appropriate geometry between the path a dispensed drop of ophthalmic drug takes and the eye. Prior art such as U.S. Pat. No. 5,558,653 "Targeted eye drop dispenser" which uses visual feedback to align an ophthalmic drug dispenser simply helps place the nozzle along the axis of the eye at an arbitary distance selected at random by the user. This is only effective if the axis of the eye and the path a dispensed drop falls are the same. The axis and path are only identical when the eye is rotated 90 degrees with respect to the horizon which can only be easily achieved lying down. Most users dispense eyedrops while standing or sitting with the eye rotated about 50 degrees back and will miss often with those types of implementations.
To efficiently dispense drugs with this invention, the user would tilt his/her head back, position the lens proximal to the eye where drug dispense is desired, align a target with his/her eye until a specified image appears thereby gauging distance, orientation and concentricity with the axis of the eye, and dispense a drop directly into the eye. Since the success rate of delivering a single drop in the desired location, i.e. the eye, will exceed 99%, the amount of waste can be reduced dramaticaly. At the same time, a visual mechanism by which the dispenser tip is prevented from gaining too close proximity and contacting the eye is provided, thus preventing contamination of the medication and its dispenser.
For years, the primary method of medically treating disorders of the eye has been via topical administration of various medications and other chemical compounds useful in combating a host of ophthalmic ailments. In fact, studies show that when measuring concentrations of these compounds at the desired target site (whether it be in the tearfilm, intracorneal, or intraocular), topical delivery equals or exceeds those concentrations obtained by systemic routes (oral or intravenous), and has far fewer systemic untoward signs and symptoms (side effects). Thus, it is no wonder that most remedies and medications are delivered via the topical route. Historically, this has been achieved via ointments, suspensions, solutions, contact lenses, collagen shields, and palpebral inserts. Far and away, the most common mode of delivery has been via topical suspensions and solutions. Typically, dispensers have fairly standard sizes and shapes (although there is some slight variation), and there is a reproducible standard drop size that is governed by the dropper (dispenser) tip. As simple as topical delivery may seem to achieve, there are various difficulties and shortcomings with current topical dispensing units (vials and bottles), many of which have not been previously or adequately addressed and solved.
The most common problem that the typical patient experiences when attempting to use an eyedrop is the inability to introduce a drop into the eye, or simply missing the eye. There are several reasons for this. First, the normal bottle tip is not clearly visible as it approaches a normal emmetropic, hyperopic, or even myopic eye. This immediately leads to the probability that the first drop will become the "test drop", landing on the cheek, forehead, or eyelashes, leading to waste and frustration. Second, there is a natural aversion to a closely approaching objects, causing the eye to wander or drift, and look everywhere but at the dispenser tip. Again, this leads to the possibility that a drop will miss. Finally, most users are not taught how to use eye drops. They are simply given the bottle and instructed to "place one drop in the eye".
The next important issue is one of waste. When a typical eye drop is introduced into the eye, the average inferior cul-de-sac only holds one-quarter to one-half of a standard drop. The remainder is either washed out down the cheek, or drained by the lacrimal system. Large strides in preventing waste were made when a dispenser tip was developed that delivered smaller drop sizes, thus eliminating a portion of waste. However, this advantage is negated if it takes several drops to gain access to the ocular surface. This issue is critical when evaluating cost to) the patient and the healthcare system. The cost problem for the patient is obvious the more drops they use, the greater the amount of money spent. With respect to the healthcare system as a whole, cutting costs are of paramount importance. In fact, many Health Maintenance Organizations (HMO's) will not let their members get refills on their ophthalmic medications more than once a month. The rationale behind this is simple. If the bottle has "x" number of drops in it, it should last "y" number of days. If the patient is not proficient with a high success ratio, then the drops will run out before the specified time allowed. This, in turn, leads to the patient either being without their valuable medications, or having to pay for the medications themselves.
Finally, there is the problem of contamination of the dispenser tip, and cross-contamination between patients. Since the tip is not clearly visible upon the approach to the ocular surface, it oftentimes will inadvertently come in contact with the eye of lid structures. This will lead to an inoculation of the tip with ocular flora, and be a potential source for spreading infection. Although sharing medications in general, especially eye drops, is always discouraged, many different people whether friends or family members, often find the ease and convenience of sharing overwhelmingly tempting. Again, this can lead to cross-contamination and, in turn, spread of infection.
This invention addresses these main issues, and solves the problems at hand. Using the lens and target system, the user is provided with a reproducible method of dispensing eye drops. If the dispenser is too far from the eye or not properly aligned on its axis, the target is not fully visible. If it is too close, another target segment becomes evident, indicating that the tip is indeed too close. When the target is appropriately visualized, the probability that the drop will enter the eye will exceed 99 percent providing that the user does not blink or uses their other hand to hold their eyelids open. If the user is able to attain this high success rate in a reproducible fashion, all of the aforementioned problems are addressed and solved: the drop is easily administered, there is a significant reduction is waste, and the chance of contamination is diminished dramatically.
Most of the current problems of efficiently dispensing ophthalmic drugs stem from user error. Therefore, it is the goal of this device to create a "user friendly" ophthalmic drug dispenser.